Pressure cooker



Dec. 12, 1950 L, FlNcH 2,534,164

PRESSURE COOKER Filed June 14, 1946 2 Sheets-Sheet 1 INVENTOR LEONARD E. FmcH 'BY w FIG. 5

ATTORNEY Dec. 12, 1950 Filed June 14, 1946 FlCa. 9

L. E. FINCH PRESSURE COOKER 2 Sheets-Sheet 2 FIG. 6

INVENTOR LEONARD E. FmcH BY yfl 60 ATTORN Y Patented Dec. 12, 1950 PRESSURE COOKER Leonard E. Finch, West Bend, Wis, assignor to West Bend Aluminum Company, West Bend, Wis., a corporation of Wisconsin Application June 14, 1946, Serial No. 676,671

6 Claims.

This invention relates to improvements in pressure cookers.

Pressure cookers of the type designed and intended for domestic use must be substantially fool-proof in operation. Often the user fails to complete the lock between the cover and the container, and after pressure builds up Within the cooker the incomplete lock will break or otherwise become disengaged and the cover will fly off endangering nearby persons. There have been times when the user, contrary to directions, will disengage the lock between cover and container while there still remains greater than atmospheric pressure within the cooker. This likewise causes the cover to dangerously jump up from the container. Many times the user will misplace the separate weight which constitutes a part of the pressure selector and regulator valve, and the temptation is present to plug the vent with any available means. This also creates a hazardous condition.

One object of this invention, therefore, i to provide a pressure cooker which will automaticall prevent the creation of greater than atmoslock between cover and container has been completely accomplished.

Another object of this invention is to provide a pressure cooker which will automatically vent the container to atmosphere upon the initiating of the unlocking of the cover.

Another object of this invention is to provide a pressure cooker the cover of which cannot be partially locked or unlocked unless the container is vented to atmosphere.

A still further object of this invention is to provide a pressure cooker in which the pressure selector member of the regulator valve is always attached to the cooker and is readily manipulated to obtain the selected pressure limit.

These objects are obtained by various means. One Way is to utilize the relative movement of the parts accomplishing the lock or unlock between cover and container to keep open the vent of the pressure regulator during all of such movement. In cookers where the cover is rotated relative to the container to accomplish the lock or unlock therebetween, the pressure regulator valve engages with and rides on a portion on the container at the beginning of the rotation of the cover and slides along such portion during the rotation to locked position. In this engaged position of the valve, the vent is open to atmosphere. Hence, if the locking movement is not completed, pressure within the container can never exceed atmosphere. Upon the completion of the locking movement the projection disengages from such portion and the valve is moved so as to close the vent. Immediately on the commencement of the reverse or unlocking rotation, the projection again engages with such portion and opens the vent to atmosphere. In cookers where the cover has no rotative movement relative to the container and a locking part is moved relative to the cover and the container to effectuate the lock, the valve may be carried by the locking member so as to ride along the cover until at the end of the closing movement of the locking part it comes into alinement with the vent which until then has been open to atmosphere. Instead of mounting the valve on the locking part, the locking part may extend over the vent except when moved to completely locked position. Only when in that position may the valve be placed on the vent. When the valve is on the vent it restrains the locking member from being slid to ward unlocked position. In all these cases the act of placing the cover on the container and ommencin the normal lockin o eration autopherrc pressure within the container until the e c g g p matically vents the interior of the cooker to atmosphere and maintains it so vented until the lock is completed. Thus pressure above atmosphere can never be attained while the cover is only partially locked to the container. Also the commencement of the unlocking of the cover likewise vents the interior of the cooker to atmosphere, and the cover cannot be removed while there is greater than atmospheric pressure in the cooker.

The novel features, which are considered characteristic of the invention, are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawings, in which:

Figure l is a view in side elevation with parts shown in fragmentary section of a pressure cooker embodying the present invention;

Figure 2 is a top plan view of the pressure cooker viewed in Fig. 1;

Figure 3 is a fragmentary top plan view of the pressure regulator comprising an element of the pressure cooker embodying the present invention with one of the selecting weights moved out of operative position;

Figure 4 is a top plan view of the pressure regu- 3 lator of Fig. 3 with both of the weights and the valve member moved out of operative position;

Figure 5 is a fragmentary side elevation view taken from the line 55 of Fig. 2;

Figure 6 is a top plan view of the pressure cooker of Fig. l with the cover shown in a halflocked position relative to the containers;

Figure 7 is a fragmentary side elevation view taken from the line l? of Fig. 6;

Figure 8 is a fragmentary sectional view taken on the line 8- of Fig. '7;

Figure 9 is a top plan view of the pressure cooker of Fig. 1 with the top placed on the container and prior to any rotative movement thereof to effect the lock therebetween; and

Figure 10 is a fragmentary side elevation view taken from the line lli ll of Fig. 9.

Referring to the drawings by reference numerals, the pressure cooker comprises a container ID which is provided with the customary handle II by which the container may be manipulated. The container it is provided at oppositely spaced portions with cover holding or retaining lugs I2 and 13. One of these lugs I3 is preferably (but not necessarily) formed at the juncture of the handle ll with the wall of the container iii. Such position causes the pouring sides of the container to be free from any projections which would interfere with the normal emptying of the contents of the container. The purpose of these lugs I2 and I3 is to limit and restrain the upward movement of the cover member I l under the influence of pressure above atmosphere generated within the container, and their size is designed to provide adequate holding strength. The cover it is disklike in shape and has a depending annular flange or skirt l5 which extends down within the container when the cover is positioned thereon. The external diameter of this flange is slightly less than the diameter of the interior of the vessel so as to have an easy fit therein. The outer wall of the flange I5 is provided with an encircling groove l6 into which is inserted a sealing ring ll' formed of rubber or other compressible and resilient materials. slightly beyond the outer cylindrical surface of the flange l5 and provides a surface-to-surface contact with the interior of the vessel is when the cover is in position. With seals of this character it is not essential to press or clamp down the cover against the container to form the seal. As pressure greater than the atmosphere is generated within the container, the cover will rise within the limits permitted by the lugs l2 and it,

andthe seal between the sealing ring ll and the vessel II) will be increased by the action of the internal pressure. In order to prevent the cover from rising beyond the limits of the holding lugs l2 and i3, it is provided with a laterally extending rim it. This rim i8 is provided with an opening it adjacent the handle 26. As shown in Figures 2, 6 and 9, the opening l 9 is spaced angularly clockwise from the juncture between the handle 28 and the cover The opening l9 of course, long enough to permit the lug l3 to pass therethrough. With this construction, to position and lock the cover It onthe container the handles Ii and it are relatively positioned as shown in Figure 9, whereupon the rim is may be inserted under the lug l2 and the flange I5 positioned within the container ill. The handle side of the cover I l may then be lowered so that the lug l3 passes through the opening Is permitting the rim It to rest flush against the upper edge of the container ill. To complete the lock the Its thickness is such that it extends cover I 4, by manipulation of the handle 20, is moved in a clockwise rotation relative to the container It until the handles are in substantial alinement as shown in Figure 2. This causes the rim it to pass under the lug I3. A small pin 2! or other like abutment positioned on the upper edge of the container it adjacent the juncture of the handle I I with said container will engage the edge of the im it at the opening is to arrest the clockwise motion of the cover when the handles are in substantial alinement. When the cover has been fully rotated from the position shown in Figure 9 to the position shown in Figures 1 and 2, the full areas of the lugs i2 and i3 have a surface-to-surface abutment with the rim [8 of the container and jointly act to keep the cover I l from rising upwardly under the infiu ence of internal pressure.

In order to prevent pressure from increasing beyond atmospheric while the cover is in a nonlock or partially locked position (such as is shown in Figure 6) or to prevent the cover from being rotated away from completely locked position when there is pressure greater than atmosphere within the container, a safety device is incorporated. This safety device in the embodiment shown herein is also utilized as a pressure regulator. However, a separate regulator may be used in addition to the safety device. In the embodiment shown herein this safety device and pressure regulator comprises a tube 22 passing through an aperture in the cover i adjacent edge. The tube 22 is hollow and provides a vent by which internal pressure may escape to atmosphere. The tube 22 is also utilized to hold in place on the top of the cover a bracket member 23 for pivotally holding various weights. To the bracket member [.3 there is hinged by means of a pin a weighted valve-carrying member haped generally as illustrated. The length of the valvecarrying member 24 from its pivotal axis to its outer edge is suficient to bring the outer edge substantially in alinement with the outer edge of the rim l8. The purpose of making the valvecarrying member it somewhat fan-shaped is to cause its outer edge to be longer than the lug I2. A cone-shaped valve 25 is mounted on the underside of the valve-carrying member Ed by a stem passing through an aperture in such member. This stem is peened or riveted to hold the valve in place. However, there is provided a loose fit between the valve 25 and the member 2 1 so that the valve can have movement with respect thereto permitting it to have a self-centering and alining action. The valve 25 is placed as near to the fulcrum or pivotal axis of the member 24 as is practical and is in alinement with th top open-- ing in the vent 22. This results in the greatest possible force tending to keep the valve closed. It has been found that when the member Ed is provided with a skirt-like depending flange a smoother operation results. The outer corners of member 24 have tooth-like downward projections 25 and 27 which in the normal closed posi-- tion of the valve are slightly spaced from the rim I8 as is shown inFigurcs 5 and 10.

The vent 22, valve-carrying member 2%, and valve 25 are positioned diametrically opposite the handle 29. When the cover it is placed on the container in the relative position shown in Figure 9, both the projections 28 and 21 are on the counter-clockwise side of the lug l2. While in this position the valve 25 is closed, and no pressure can be built up within the container as the cover not being secured will rise and per mit the escape of such pressure as it forms. However, when the cover I4 is rotated clockwise to commence the locking thereof, the projection 21 rides up on and along the top of the lug l2. This action causes the outer end of the valvecarrying member 24 to be raised upwardly and the valve 25 to be moved to open position as shown in Figures 7 and 8. It will be understood that the hinge or pivotal connection between the.

member 24 and the bracket member 23 is surficiently loose to permit some twisting in connection with the tilting However, the engagement between the projection 25 and the top of the rim l 8 coacts with the upward movement of the projection 21 to effect sufficient raising of the outer end of the member 24, without a binding action on the pivot pin, to open the valve. If the rotation of the cover is stopped part way through the locking motion such as is shown in the relative position illustrated in Figure 6 the valve 25 will remain open and substantially no pressure greater than atmosphere can be built up within the container. Thus the danger attendant an impartial or incomplete lock is eliminated. When the clockwise locking movement has been completed and the cover handle 2E! is in substantial alinement with the container handle I l, the pro jection 21 will have just slid off of the top of the lug l2 and the weight of the member 24 will again force the valve 25 to close the vent. This posiii:

tion, is illustrated in Figures 1, 2 and 5. If for some reason the user of the pressure cooker attempts to remove the cover l4 while there is greater than atmospheric pressure in the container, it will be necessary to rotate the cover in a counter-clockwise direction from the position shown in Figure 2. If the interior pressure is great, there will be such a frictional resistance between the lugs I2 and I3 and the rim l8 that such movement could not be performed by one not specially trained or skilled. However, if the interior pressure is still above atmosphere but not greatly in excess thereof, such movement may be com menced. In such event and upon the initiating of such movement, the tooth 21 immediately rides 4;

up to and along the top of the lu I2. This at once opens the valve 22 venting the interior of the vessel to atmosphere. Such venting in all practical instances permits a sufliciently rapid lowering of the pressure within the vessel so that by the time the unlocking is completed there will not remain sufiicient pressure to cause the cover to dangerously fly off the container.

When it is desired to utilize the safety device also as a pressure regulator as well as a safety device and to provide for the pre-selecting of various pressures, an auxiliary weight 28 may also be hinged to the bracket member 23. When a pressure higher than that obtained by the use of the valve-carrying member 24 is desired, the auxiliary weight 28 is manually thrown over so as to rest upon the top of the member 24 as is shown in Figure 1. If the lower pressure is desired, the auxiliary weight 28 is pivoted away from the valve-carryin member 24 to the position shown in Figure 3 where it will have no effect upon keeping the valve 25 in closed position. The pressures derived by the use of the members 24 and 25 may be stamped on the upper surface of those members so that the user may make the proper desired selection. In operation as a pressure regulator, when the interior pressure reaches pounds it will be sufiicient to cause the valve 25 to raise up both members 24 and 28, therebv permitting escape of steam through the vent 22 thus keeping the pressure at that desired value. If only the member 24 is used, the valve will open and pressure will escape when it reaches 10 pounds.

In the event that the valve should become stuck through some unforeseen reason and the pressure within the vessel exceed the amount of 15 pounds above atmosphere, it is desirable to have a standard safety plug such as that designated 29 which will blow out at a pressure above that amount but substantially less than the breaking pressure of the vessel. Whenever the vessel is being transported while there is an interior pressure substantially equal to that set by the pressure regulator, there is a tendency to flip the valve-carrying member 24 and weight 28 about their pivot to a point where they will fall against the top of the cover l4. This will permit a small geyser of steam to shoot out through the vent 22 which may startle the person handling the vessel. In order to prevent this, the member 24 is provided with a spring 39 which is held by a small pin 3! to the underside of the member 24. The spring has an end which just engages an edge of the bracket member 23 when the member 24 is raised up by the action of the lug I2 as heretofore described. Hence the spring 30 in no way interferes with the normal action of the valve 25 and yet it restrains any further upward movement of the member 24 under the force of escaping steam. However, if it is desired to fully open the valve 25, the spring will deflect slightly under manual force and permit the member 24 to be swung fully out of the way. The spring 3!] is sufficiently strong, however, to prevent escaping steam and jiggling motion from flipping the member 24 completely over, thus fully exposing the vent.

This application is intended to cover such changes and modifications as come within the spirit of the invention or the scope of the follow ing claims.

I claim:

1. In a pressure cooker, a container having a cover holding lug, a cover for said container. sa d cover having a laterally projecting rim insertable under said lug. said cover being rotatable with respect to said container for a predeters mined distance to efiect a complete lock between said container and cover. a vent for said container. a loosely hinged valve for said vent movable with said cover, said valve having spaced projections the ends of which normally are spaced slightly from said rim, said valve and lug being relatively angularly spaced so that for said predetermined distance one of said projections is rideable up and on said lug and the other projection is rideable on said rim to raise said valve and open said vent.

2. In a pressure cooker, a container having oppositely positioned cover holding lugs, a cover for said container having a laterally projecting rim, an opening in said rim large enough to permit one of said lugs to pass therethrough where by said cover may be placed on said container by inserting the rim under one of said lugs and passing the other lug through said opening, rotation of said cover when in said position for a predetermined distance causing said other lug to also be positioned completely over said rim, a vent in said cover, and a loosely hingedly mount- ,ed valve for said vent rotatable with said cover,

being angularly placed relative to one of said lugs when said opening is in alinement with a lug so that upon initiating said rotation oneof said projections will ride up said lug for said predetermined distance and the other projection will bear against said rim to raise said valve and open said vent.

3. In a pressure cooker, a container, 2. cover seatable upon said container to close the same, interengageable locking means for locking said cover to said container, said means being operated from fully locked to fully unlocked position by relative rotation of said cover with respect to said container for predetermined distance, a container vent in said cover, a valve-carrying member hingedly mounted to said cover and m having an extending end, a valve carried by said member in alinement with said vent, said extending end being swingable up and down with respect to said cover from low position in which said valve closes said vent to high position in which said valve opens said vent, said extending end when. inthe low position thereof having a prescribed path as said cover is rotated said predetermined distance, and an abutment on said container positioned in said prescribed path and engageable with said end whereby said end must be raised to high position during rotation of said cover for said predetermined distance to operate said locking means from fully locked to fully unlocked position.

4. In a pressure cooker, a container, a. cover seatable upon said container to close the same, interengageable locking means for locking said cover to said container, said means being operated from fully locked to fully unlocked position by relative rotation of said cover with respect to' said container for a predetermined distance, a pressure regulator valve for said pressure cooker, an operating member for said valve normally biased to pressure-regulating position and movable to open position to cause said valve to vent said pressure cooker, and a cam portion adapted when in engagement with said member to move said member to and maintain said member in said open position, said cam portion being movable relative to said member upon initiating said relative rotation of said cover with respect to said container to Cause said cam portion to engage said member and move said member to open position, said cam portion being long enough to remain in engagement with said member while it moves relative thereto during the relative rointerengageable locking means for locking said cover to said container, said means being operated. from fully unlocked to fully locked position by relative rotation of said cover with respect to said container for: a predetermined dism tance, a vent for said container, a hinged valveoperating member normally biased to vent-closing position and upwardly swingable to vent open position, a valve carried by said member and moved thereby from normally biased closed position to open position, and a camming surface Zia having a path of movement relative to said memher and engageable therewith while moving in said path to swing and hold said member in. open position, said camming surface being movable in said path by the relative rotation of said cover with. respect to said container for said predetermined distance 6. In a. pressure cooker, a container having a cover-holding lug, a cover for said container rotatable relative to said lug for a predetermined distance to move said cover to and from fully unlocked and fully locked positions, a vent for said container, a valve for said vent normally biased to closed position and movable to open position, an operating member for said valve movable from closed to open position to bring said valve to open position, said member when in closed position having a prescribed path relative to said lug as said cover is rotated relative V, thereto, said member engaging said lug and being moved thereby to open position during rotation of said cover for said predetermined distance.

LEONARD E. FINCH.

REFERENCES CITED The following references are of record. in the file of this patent:

UNITED STATES PATENTS.

H Number Name Date 1,494,487 Jacobs May 20, 1924 1,823,595 Ducroux Sept. 15, 1931 2,191,975 Stephens Feb. 27, 1940 2,436,566 Goldberg Feb. 24, 1948 FOREIGN PATENTS Number Country Date 559,659 Germany Sept. 22, 1932 

